Timeout waiting to lock artifact cache what's wrong?

Question

Java

Hello everyone, I ran into a problem:
I create / open a project in AS and here is an error in the console:

Error:Timeout waiting to lock artifact cache (C:\Users\nnacc\.gradle\caches\modules-2). It is currently in use by another Gradle instance.
Owner PID: 9620
Our PID: 8808
Owner Operation: resolve configuration ':classpath'
Our operation: resolve configuration ':classpath'
Lock file: C:\Users\nnacc\.gradle\caches\modules-2\modules-2.lock

What could be the problem?
the only answer I found was "delete or rename the caches folder" - but it didn't work out. some application works with it (AS, etc. closed)